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            <h2 class="title"><a id="dpl_example"></a>Chapter 6. A DPL Example</h2>
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        <p>
          <b>Table of Contents</b>
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          <dt>
            <span class="sect1">
              <a href="dpl_example.html#vendorclass">Vendor.java</a>
            </span>
          </dt>
          <dt>
            <span class="sect1">
              <a href="inventoryclass.html">Inventory.java</a>
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          <dt>
            <span class="sect1">
              <a href="mydbenv-persist.html">MyDbEnv</a>
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          </dt>
          <dt>
            <span class="sect1">
              <a href="dataaccessorclass.html">DataAccessor.java</a>
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          </dt>
          <dt>
            <span class="sect1">
              <a href="dpl_exampledatabaseput.html">ExampleDatabasePut.java</a>
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          <dt>
            <span class="sect1">
              <a href="dpl_exampleinventoryread.html">ExampleInventoryRead.java</a>
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      <p>
                In order to illustrate DPL usage, we provide a
                complete working example in this chapter. This example
                reads and writes inventory and vendor information for a
                mythical business. The application consists of the
                following classes:
        </p>
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            <p>
                                Several classes used to encapsulate our
                                application's data. See
                                <a class="xref" href="dpl_example.html#vendorclass" title="Vendor.java">Vendor.java</a>
                                and
                                <a class="xref" href="inventoryclass.html" title="Inventory.java">Inventory.java</a>.
                        </p>
          </li>
          <li>
            <p>
                                A convenience class used to open and close
                                our environment and entity store. See
                                <a class="xref" href="mydbenv-persist.html" title="MyDbEnv">MyDbEnv</a>.
                        </p>
          </li>
          <li>
            <p>
                                A class that loads data into the store. See
                                <a class="xref" href="dpl_exampledatabaseput.html" title="ExampleDatabasePut.java">ExampleDatabasePut.java</a>.
                        </p>
          </li>
          <li>
            <p>
                                Finally, a class that reads data from the
                                store. See
                                <a class="xref" href="dpl_exampleinventoryread.html" title="ExampleInventoryRead.java">ExampleInventoryRead.java</a>.
                        </p>
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              <h2 class="title" style="clear: both"><a id="vendorclass"></a>Vendor.java</h2>
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        <p>
                        The simplest class that our example wants to store contains
                        vendor contact information. This class contains no
                        secondary indices so all we have to do is identify it
                        as an entity class and identify the field in the
                        class used for the primary key.
                    </p>
        <p>
                        In the following example, we identify the
                        <code class="literal">vendor</code> data member as containing the
                        primary key. This data member is meant to contain a
                        vendor's name. Because of the way we will use our
                        <code class="classname">EntityStore</code>, the value
                        provided for this data member must be unique within
                        the store or runtime errors will result.
                    </p>
        <p>
                        When used with the DPL, our
                        <code class="classname">Vendor</code> class appears as
                        follows. Notice that the <code class="literal">@Entity</code>
                        annotation appears immediately before the class
                        declaration, and the <code class="literal">@PrimaryKey</code>
                        annotation appears immediately before the
                        <code class="literal">vendor</code> data member declaration.
                    </p>
        <pre class="programlisting">package persist.gettingStarted;

import com.sleepycat.persist.model.Entity;
import com.sleepycat.persist.model.PrimaryKey;

@Entity
public class Vendor {

    private String address;
    private String bizPhoneNumber;
    private String city;
    private String repName;
    private String repPhoneNumber;
    private String state;

    // Primary key is the vendor's name
    // This assumes that the vendor's name is
    // unique in the database.
    @PrimaryKey
    private String vendor;

    private String zipcode;

    public void setRepName(String data) {
        repName = data;
    }

    public void setAddress(String data) {
        address = data;
    }

    public void setCity(String data) {
        city = data;
    }

    public void setState(String data) {
        state = data;
    }

    public void setZipcode(String data) {
        zipcode = data;
    }

    public void setBusinessPhoneNumber(String data) {
        bizPhoneNumber = data;
    }

    public void setRepPhoneNumber(String data) {
        repPhoneNumber = data;
    }

    public void setVendorName(String data) {
        vendor = data;
    }

    public String getRepName() {
        return repName;
    }

    public String getAddress() {
        return address;
    }

    public String getCity() {
        return city;
    }

    public String getState() {
        return state;
    }

    public String getZipcode() {
        return zipcode;
    }

    public String getBusinessPhoneNumber() {
        return bizPhoneNumber;
    }

    public String getRepPhoneNumber() {
        return repPhoneNumber;
    }
} </pre>
        <p>
                            For this class, the <code class="literal">vendor</code> value is set for an individual
                            <code class="classname">Vendor</code> class object by
                            the <code class="methodname">setVendorName()</code>
                            method. If our example code fails to set this
                            value before storing the object, the data
                            member used to store the primary key is set to a
                            null value. This would result in a runtime
                            error.
                    </p>
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